Input, process, output using arrays

Got it! This site uses cookies. You consent to this by clicking on "Got it!" or by continuing to use this website.nbsp; Note: This appears on each machine/browser from which this site is accessed.

c go java js lua py vbs rkt scm pro

We previously covered the following.

If anything here is not familiar, go back and review where it was previously covered.

The same problem is now solved where arrays are used to separate input, processing, and output.

Arrays can be used to separate input, processing, and output.

Suppose that there are a maximum of 100 data numbers in the input (which does not include any header or trailer values - they are not data numbers).

The data numbers form a logical list. A list is a sequence of items.

There are (at least) two ways to logically represent a list of n items.

A list from 0 to n-1.
A list from 1 to n.

Since an array starts at index 0, a list of n items from 1 to n requires an array of n+1 items.

Here is one way to represent a list of items from 1 to 100 using on array of 101 items.

const int DATAMAX1 = 100;
int dataList1[DATAMAX1+1];

The constant (named literal) DATAMAX1 (all upper case, by convention) is set to 100.
The array dataList1 representing the data list has DATAMAX1+1 elements, each of type int.

Note: In the code examples that follow, there is no check to insure that more than DATAMAX1 data numbers are added to the list.

The input should get the input into the array. Here is an example using a header loop where dataLen1 is known.

for (int dataPos1=1; dataPos1 <= dataLen1; dataPos1++) {
	scanf("%d",&dataValue1);
	dataList1[dataPos1] = dataValue1;
	printf("\tItem %d is %d\n",dataPos1,dataValue1);
	}

In a counter or header loop, the data value can be read directly into the array element as follows.

for (int dataPos1=1; dataPos1 <= dataLen1; dataPos1++) {
	scanf("%d",&dataList1[dataPos1]);
	printf("\tItem %d is %d\n",dataPos1,dataList1[dataPos1]);
	}

Note: In a trailer or endfile loop, one extra value is needed, so the array should then have DATAMAX1+2 elements instead of DATAMAX1+1 elements.

The processing should go through the data list computing the cumulative sum over the data list.

dataSum1 = 0;
for (int dataPos1=1; dataPos1 <= dataLen1; dataPos1++) {
	dataValue1 = dataList1[dataPos1];
	dataSum1 += dataValue1;
	printf("\tSum of elements 1 to %d is %d\n",dataPos1,dataSum1);
	}

Here, a separate data value variable dataValue1 is used.

In some cases, the array element can be access directly in computing the cumulative sum.

dataSum1 = 0;
for (int dataPos1=1; dataPos1 <= dataLen1; dataPos1++) {
	dataSum1 += dataList1[dataPos1];
	printf("\tSum of elements 1 to %d is %d\n",dataPos1,dataSum1);
	}

Here is the C code.

#include <stdio.h>

int main() {
	int dataLen1;
	int dataValue1;
	int dataSum1;
	const int DATAMAX1 = 100;
	int dataList1[DATAMAX1+1];

	printf("Input:\n");
	printf("\n");
	// header loop
	scanf("%d",&dataLen1);
	printf("\tItems expected: %d (header loop)\n",dataLen1);
	printf("\n");
	for (int dataPos1=1; dataPos1 <= dataLen1; dataPos1++) {
		scanf("%d",&dataValue1);
		printf("\tItem %d is %d\n",dataPos1,dataValue1);
		dataList1[dataPos1] = dataValue1;
		}

	printf("\n");
	printf("Process:\n");
	printf("\n");
	dataSum1 = 0;
	for (int dataPos1=1; dataPos1 <= dataLen1; dataPos1++) {
		dataValue1 = dataList1[dataPos1];
		dataSum1 += dataValue1;
		printf("\tSum of elements 1 to %d is %d\n",dataPos1,dataSum1);
		}

	printf("\n");
	printf("Output:\n");
	printf("\n");
	printf("\tThe sum of %d values is %d.\n",dataLen1,dataSum1);
	return 0;
	}

Here are some examples of input and output for the above program code.

Here is an example input.

For the above example input, here is the expected output.

Input:

	Items expected: 3 (header loop)

	Item 1 is 23
	Item 2 is 57
	Item 3 is 75

Process:

	Sum of elements 1 to 1 is 23
	Sum of elements 1 to 2 is 80
	Sum of elements 1 to 3 is 155

Output:

	The sum of 3 values is 155.

Here is the C code.

#include <stdio.h>

int main() {
	int dataLen1;
	int dataValue1;
	int dataSum1;
	const int DATAMAX1 = 100;
	int dataList1[DATAMAX1+1];

	printf("Input:\n");
	printf("\n");
	// trailer loop
	int dataPos1 = 0;
	scanf("%d",&dataValue1);
	while (dataValue1 >= 0) {
		dataPos1 += 1;
		printf("\tItem %d is %d\n",dataPos1,dataValue1);
		dataList1[dataPos1] = dataValue1;
		scanf("%d",&dataValue1);
		}
	dataLen1 = dataPos1;
	printf("\n");
	printf("\t%d items found (trailer loop)\n",dataLen1);

	printf("\n");
	printf("Process:\n");
	printf("\n");
	dataSum1 = 0;
	for (int dataPos1=1; dataPos1 <= dataLen1; dataPos1++) {
		dataValue1 = dataList1[dataPos1];
		dataSum1 += dataValue1;
		printf("\tSum of elements 1 to %d is %d\n",dataPos1,dataSum1);
		}

	printf("\n");
	printf("Output:\n");
	printf("\n");
	printf("\tThe sum of %d values is %d.\n",dataLen1,dataSum1);
	return 0;
	}

Here are some examples of input and output for the above program code.

Here is an example input.

For the above example input, here is the expected output.

Input:

	Item 1 is 23
	Item 2 is 57
	Item 3 is 75

	3 items found (trailer loop)

Process:

	Sum of elements 1 to 1 is 23
	Sum of elements 1 to 2 is 80
	Sum of elements 1 to 3 is 155

Output:

	The sum of 3 values is 155.